1. Field of the Invention
The present invention relates to tractor trailer rigs and more particularly relates to an improved roller slide mechanism for tandem wheel vehicles wherein a sliding subframe portion connected to the vehicle body carries wheels with air operated brakes, wherein an interface connects an operator for locking a pin to fix the position of the sliding portion with the air supply line to the brakes.
2. General Background
A common arrangement for transporting freight is a tractor trailer rig commonly referred to as an "eighteen-wheeler". Such tractor trailer rigs typically employ a short but powerful "tractor" portion which is normally a diesel powered truck having a coupling at its rear end portion for attaching the trailer portion thereto. The trailer is much longer than the tractor portion and includes at its rear end portion a plurality of wheels.
There are commercially available frames which use a moving, usually sliding connection between the wheels and the frame of the trailer so that the wheel base position of the wheels can be varied with respect to the trailer frame. The adjustable vehicle frames, adjustable running gear, adjustable slide assemblies and load equalizing devices as they are sometimes called are known in the art. Such assemblies are provided to compensate for widely varying load conditions for trailers. Frequently, trailers and like vehicles cannot always be loaded equally throughout their length with the result that the loads bearing on the wheels supporting the vehicle are not always uniform and many prior devices have been devised to compensate for this unbalanced load condition. Such sliding support arrangements for the wheels are commercially available, and manufactured for example by Hutchens, such as for example shown and described in U.S. Pat. No. 3,372,946 issued to C. T. Hutchens and entitled "Roller Slides for Trailer". U.S. Pat. No. 3,372,946 is hereby incorporated herein by reference.
Subframes use a sliding portion and one or more spring loaded locking pins that engage holes on both the sliding portion and the fixed portion of the subframe. Typically a rod which is hand actuated is pulled to rotate a shaft which engages or disengages the locking pins.
The problem with such manual locking arrangements is that the pins typically are a very long distance from the cab of the truck and it is aggravating and time consuming for the operator of the truck to leave the cab, walk to the rear of the truck and then manually engage or disengage the locking pins.
There are several other patents naming C. T. Hutchens as patentee including U.S. Pat. No. 2,907,576 entitled "Hydropneumatic Equalizing Suspension for Vehicles", U.S. Pat. No. 2,968,495 entitled "Mechanism for Steering Tandem Wheels of a Tractor Trailer Assembly", and U.S. Pat. No. 3,123,377 entitled "Tandem Suspension for Eliminating Brake Hopping".
Another patent that describes a mechanism for adjustably interconnecting a vehicle running gear with the vehicle body is described in U.S. Pat. No. 3,126,209 entitled "Means for Adjustably Interconnecting a Vehicle Running Gear and Body". The '209 patent uses a cam actuated handle to operate locking pins.
In U.S. Pat. No. 3,224,522 entitled "Vehicle Spring Axle Loading Control System", a fluid control system enables the operator to control at will the relative inflation of respective air bags stacked in multiples. These air bags are pneumatic springs arranged to provide variable support for the vehicle frame from the mechanical spring structure forwardly and rearwardly of the tag axle. Air supplied to the pneumatic spring through a pressure supply line which leads to a valve normally located in the cab of the vehicle. A compressor delivers through a supply pipe air under pressure.
U.S. Pat. No. 3,533,641 entitled "Power Actuated Undercarriage for Mobile Home" illustrates a power actuated mechanism for facilitating the conversion of a mobile home unit between transit and occupancy condition.
U.S. Pat. No. 3,659,671 entitled "Tag Wheel Lift" describes a spring seat mounted on each side of a pivot shaft which is mounted transversely of a truck frame between the drive wheels and the tag wheels and is pivoted by a rocker arm pivotally connected to a piston rod of a hydraulic cylinder.
A sliding axle assembly for flat deck trailers is the subject of U.S. Pat. No. 3,963,259. In the '259 patent, two spaced and parallel V-tracks are secured to the underside of a trailer body and engaging a plurality of rollers having V-grooves therein which are mounted upon the main undercarriage frame thus facilitating easy movement and adjustment of the undercarriage relative to the trailer body. Locking means are provided at intervals between the undercarriage and the trailer body so that the two may be locked together and a plurality of selective positions. This construction keeps the undercarriage in true alignment with the trailer frame without the need for side thrust rollers or guides. Furthermore the V-tracks maintain engagement with the V-rollers due to the weight of the trailer frame.
Other patents disclosing tandem axle suspensions include the King U.S. Pat. No. 4,200,267; the Carstensen et al. U.S. Pat. No. 4,284,156 and the Goth U.S. Pat. No. 4,344,642.
The wheels of the trailer type which use such subframes such as the Hutchens Model 8-8000 normally have brakes which are air operated. The air supply line extends aft of the tractor trailer rig, so that air can be supplied to the wheels.